Relief valve for rotary pumps



April 5,1192?. 1,623,315

fJ. jR. KINNEY'v RELIEF VALVE F013 ROTARY PUMPS y Filed Jun'es, 1926 l Patented Apr.i 5, 1927. l .Y y

IUfNl'l'liiD SI'ESv PATENT OFFICE.V y

JUSTUS`Y`R. KINNEY, F JAMAICA PLAIN, MASSACHUSETTS.

RELIEF VALVE FOR ROTARY PUMPS.

Application led June 5, 1926I Serial No. 113,873.

`closed before t-he piston of the pump passes it, thereby preventing any air forced into the valved outlet from escaping into the piston chamber as soon as the piston passes this outlet.

This object is attained by the mechanism illustrated in the accompanying drawing;

For the purpose of illustrating the invention, one preferred form thereof `is illustrated inthe drawings, .this form having been found to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized, and the 1nvention is not limited to the precise arrangement and organization of these instrumentalities as herein shown and described except as required by the scope of the appended claims. Y

Of' the drawings:

Figure 1 represents'av vertical section of a pump embodying the principles of the present invention.

Figure 2 represents a section on line 2, 2, on Fig. 1 showing the main discharge from the pump, land Y Figure 3 represents a section online 3, 3 on Fig. l and showing the .relief valve closed.

Similar characters indicate like parts throughoutthe several figures of the drawmg.

In the drawings, 10 is a casing having extending laterally therethrough a cylindrical chamber 11 anda compartment 12 located above the chamber' 11 and communieating therewith by means of a semi-cylindrical passage 13. The casing 1-0 has secured to its opposite ends closing plates 14, 15 in which' is disposed a rotatable shaft 17 .1

An inlet ipe -19 communicates with the upper end of) the compartment 12.

The shaft 17 extends through the center of the chamber 11 and has keyed thereto. a

cam member 20 which is surrounded by anL annularv piston 21 having a laterally extending blade 22 which extends through a slot formed in an oscillating pin '23 disposed in and fitting the lpassage 13, l

The shaft 17 extends through the cam member 20 at one side of its center forming an eccentric, thereby causing the piston 21 to Contact at one point with the cylindrical wall of the chamber 1l during the entire rotation of the shaft 17.

The blade 22 has a pocket 24 extending inwardly from its outer end, one wall 25 of which is vprovided, with the port 26 through which gas is admitted to the chamber 11 from compartment 12 at stated times during the rotation of the shaft 17.

'The lower end of the port 26 is considerably removed from the periphery of the piston so that during Aa part of the revolug The cam member'20 is preferably coredv out with openings at the ends in .which are disposed closing plugs 32.

Closely adjacent one side ofthe passage 13 on the discharge side of the pump the casing 1() is provided with a plurality of discharge ports- 33 extending into a pocket B4, the opposite ends of whichlhuve narrow extensions 35 in which are positioned the metal.

This valve 36 normally closes the ports 33 and has superimposed thereon a follower 37 forced downwardly by a spring 38, the curved upper portions of which bear against a rib 39 forming apart of the discharge nozzle 40.

As will be noted in Fig. 1 this rib 39 isl narrower than' the passage 41 extending from the bottom of said nozzle.

The lower face of the follower 37 has a pluralizy of cross ribs 42 which bear on the valve 36 leaving space between these ribs through which the gas may freely pass.

During the operation of the pump the shaft 17 rotates in the direction of arrow a opposite ends of the valve 36 of thin spring are closed.

on 1, and when the piston 21 is in the position shown in said Fig, 1 both the inlet 26l and outlet 33 from the chamber l1 pin23 about its axis and as the piston conf. tinues to move forward' said blade 22 will commence, to move downwardly until the piston reaches a position c in whlch the lower end of the port 26 will register with the iiat face 31 of the slotted pin 23.

Further rotation of the piston will un-V `cover the port 26 and permitgas to be drawn from the pockets 24 into the chamber 11.

Where it will beforced ahead of the piston to the discharge outlet ports 33, in the nextl cycle of the piston.

' The port 26 will remain open until the piston 21 reaches a position b in whichthe port 26 will be closed and remain closed until the piston again reaches the position` in 26 register's1-' operated, thereby greatly reducing the power which the-lower endofz port with the'- at'face 31.,

While the contacting point of the piston 21 is vtraveling from b to c the supplyof gas to the chamber 11 is entirely cut ofi' and as the iston continues to rotate in the ldirection oi? arrow a the gas in advancefof'said piston 2l will be compressed, this increased pressure forcing the valveplate36 romits' seat and permitting the 'gas-to `be..discha1',f,g'ed`,

throu h the openings 33 'into the-pocket 34 and t en lthrough the outlet 40.

When the last lof the gas in advance of4 the piston is abouttofbe orced throughthe openings 33, the vport 26 will be closed andv nonewsupply of gas'will be admitted until the piston attains theposition c.

Iecanu 20 is slightly shorter than thel space between the'v inner faces of the end 'plates'.14, 15 and consequently any lubricant admitted to the chamber l1 forms a film at each end ofthe cam 20, said lubricant passing fromone end to the other through the grooves l This film of lubricant 'also enters recesses The grooves in the blade 22 do'not extend 'to the outer end thereof and .therefore the oil in these grooves cannot escape therefrom.

It is obvious, therefore, that all the movlchamber 11 and the amount of oil or lubricant can be regulated by means of a needle v valve, as shownin said copending application.

ports into l movement the blade To the outlet side of the casing l10 is secured a housin 56 having a chamber 57 therein communicating :with the main chamber 11by a cone-shaped opening 58to which' the `.valve 591is fitted. `This opening 58 is formed in an end plate 15.- v ,v

yThe valve 59 has astem 60, theV end of vwhich extends into acyli'ndrical pocket 61 whichserves as a guide tor said stein 60 pressure oifgas within'themainchamber 11 reaches a predetermined limit.` -The threaded tothe end-of the housin outer end offsaid member 7 0 being. ltiet-sided as at 71, providing a means whereby said member 7 Oinaybe adjusted to vary the tension of thesprlng 62. y

At anyfflofvv pressure the opening l58 is closedA and ythere is no escape for 4 the gas therethrough. 4 From the ,housing -extendsfap-ipe 63, the. other end of which `communicates with thek com artmentj12-i o L "The o ject of' this laypass 63 is tomake the pump run morefveasi'ly. when it is first pocket 6l is formed ina member 70 ber v1,1 isvfilled with gas under atmospheric4 .pressure and this pressure offers considerable resistance to4 the ,rotationV of the piston l21. By providingthe, by-,pass v63V this gasjgin "advancefof the jrota'ting piston will pass through the by-pass into the'compartmentn12 until the ycontacting pointv on the piston passes the .QPeningS from which point the r 56, the' `gas in advance of the piston will beforced from the chamber 11 through ythe openings ber passes through the pipe 63 'and the remainder passes through the dischargeopen# ings 33 and escapes, vthe pressure lin the chamber 11 will be gradually decreased to a point where it will be insufficient to move the valve 59 `from itsseat. t

yWhen this limithas been reached the gas# v remaining in the chamber will all be dis l chargedthrough the openings, 33 until ay Vperfect vacuum is created ill-the' chamber 11,

tao

and at this time very little power is requiredY to rotate the piston 21, as there remains inthe chamber .no gas to retard its movement A itil the ribs 42 and pass noiselessly into the pocket 34 and thence through the outlet 40,

It Will be noted t-hat normally the innery siderable gas would enter the entrance 58 and before the valve could close the contacting point of the piston 2l wuld pass the eu-` trance 5S.

This would permit the gas thus collected in the entrance to escape into the chamber l1 behind the piston 21 as it continued toadvance. v i

As a consequence it was found diliicult to create an absolutely perfect vacuum which is the particular object desired to be atta-ined. y

The desired result is achieved` however, by locating the entrance 58 to the by-pass in the end wall of the chamber ll as by so locating the relief valve opposite a broad end face of the piston, the valve 59 is given time to entirely close with its inner end Hush with the inner face of the end Wall 1 5 before the piston 21 commences to uncover the entrance 58a Consequently no gas-entering the entrance 58 can escape back into the chamber as it is wholly coveredV by piston 21 until the valve 59 is again closed.

This is of the greatest importance as by thus locating the relief valve the pump may be Aoperated to quickly create a perfect vacuum in any enclosure.

This makes a most effective vacuum pump which will be noiseless in operation and which requires very little power to actuate- Itis believed that the operation and many advantages of the invention will be understood without further description.

Havingr thus described my invention,I claim- 1. ln a device of the classdescribed, a casing having a. cylindrical piston chamber therein provided with an inlet thereto and an outlet therefrom; a piston revoluble therein and contacting' at one pointwith the cylindrical Wall of said chamber, the ends of said piston contacting with the end Walls of said chamber; a by-pass communicating With an opening-in the Wall at one end of said piston chamber; and a valve closing said by-pass.and adapted to `be opened when the pressure Within said chamber exceeds a predetermined limit.

2. In a device ofthe class described, a casing having a cylindrical piston chamber therein provided with an inlet thereto and an outlet therefrom; a piston revoluble therein and`contacting at one point with the cylindrical Wall of vsaid chamber, the ends of said piston contacting with the end Walls of said chamber; a by-pass from one end of said piston chamber;and a valve closing said by-pass and adapted to. be

opened when the pressure Within said cham ber exceeds a predetermined limit, the inner end of said valve when closed being flush with said end wall.

v3. In a device of the class described, a

casing haying a cylindrical piston chamber therein provided with an inlet thereto and an outlet therefrom; av piston revoluble therein and contacting at one point With the cylindrical Wall of said chamber, the ends of said piston contacting With the-end walls of` said chamber; a by-'pass communieating with an opening in the Wall at one end of said pistonchamber and considerably removecl-from the outlet from said chamber ;fand a valve closing said by-pass and adapted to be opened when the pressure within said chamber exceeds a predetermined limit.

Je.' 4In a. device of the class described, a casing having a cylindrical piston chamber therein provided with an' inlet thereto and`` an outlet therefrom; a piston revoluble therein and contacting at one point with the cylindrical wall of said chamber; a by-pass from the outlet side of said chamber lto the inlet side thereof; and a valve'in tie entrance to said bypass adapted tx) be opened as the piston approaches said entrance and the pressure within the chamber exceeds a predetermined limit and is adapted to' be fully closed before the piston uncovers said entrance.

Signed by me at 74:6 Old South Bldg., Boston Mass., this4th day of June, 1926.

f JUSTUS R. KINNEY. 

